Acute and Chronic Effects of Three Pharmaceutical Drugs on the Tropical Freshwater Cladoceran Ceriodaphnia silvestrii

Among emerging contaminants, pharmaceuticals are one of the most relevant groups of substances found in aquatic environment, due to their universal use, specific physical-chemical properties, and mode of action in aquatic organisms at low concentrations. Considering the magnitude of concentrations and the considerable small amount of information about their potential ecotoxicological effects on wildlife (especially towards organisms from tropical areas), the present study intended to assess the acute and chronic effects of three pharmaceuticals (the analgesic acetaminophen, the anti-inflammatory diclofenac, and the antihypertensive propranolol) in the tropical crustacean species Ceriodaphnia silvestrii. Results of acute exposures showed a considerable variation in toxicity among pharmaceuticals: acetaminophen (EC50 = 40.3 mg L-1) < diclofenac (EC50 = 37.9 mg L-1) < propranolol (EC50 = 3.17mg L-1), C. silvestrii being more sensitive to the drug propranolol. Data of chronic toxicity tests showed the occurrence of reproductive adverse effects, but also stimulatory phenomena. Propranolol caused a significant increase in fecundity for the concentrations up to 0.0313 mg L-1, and the rate of population increase was significantly augmented from the lower concentration tested. Considering these results and the wide distribution of C. silvestrii in tropical regions, we suggest the use of this species to be used as test organism in ecotoxicity assays performed in such areas, especially for biomonitoring and/or the determination of effects of pharmaceutical drugs.